If one person or vehicle joins another, they move or go to the same place, for example so that both of them can do something together.

If you join an organization, you become a member of it or start work as an employee of it.

If you join an activity that other people are doing, you take part in it or become involved with it.

If you join a queue, you stand at the end of it so that you are part of it.

To join two things means to fix or fasten them together.

If something such as a line or path joins two things, it connects them.

If two roads or rivers join, they meet or come together at a particular point.

A join is a place where two things are fastened or fixed together.